Signaling system



. 2, 1924, LM'MW O. B. BUCHANAN SIGNALING SYSTEM Filed Aug. 18 192:

INVENTOR Omar B Bach 0mm ATTORNEY EPatented cc. 2, l924l.

OMAR B. BUCHANAN, OI -WILKINSBURG, PENNSYLVANIA, ASSIGNOR T WESTING- HOUSE ELECTRIC 8t lVLA-N-UFAC TURING COMPANY, A. CORPORATION OF BENNSYL- i vnma.

SIGNALING SYSTEM.

App catio le new 1921- sen :No- 49 34- T al h n i may B it k n ha One; .B- BIIQH-e aN,

a c ti n o th t d States, a a res dent of VVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Signaling Systems, of which the following is a specification. a

a My invention relates to wireless systems and more especially to wireless signaling systems.

In its broad aspect, the object of my invention is to provide simple and efiicient means for controlling the radiation of energy from wireless transmission systems.

More specifically, one object of my invention is to provide an improved radio transmission system wherein the wave length of the radiantenergy is maintained constant and wherein a uniform load is maintained upon the source of energy during the signaling and non-signaling periods.

Another object of my invention is to provide a signaling system which is especially adapted to are transmissionsystems in that signaling may be effected without interrupting the operation of the are.

Still another object of my invention is to provide a signaling system in which the sparking at the key contacts is reduced to a minimum.

According to my invention, 1 provide a simple and efficient signaling system which obviates many of the difliculties heretofore encountered. One way to practice my'invention is to provide a source of radio-frequency currents and toassociate in parallel relation therewith. an antenna or work circuit and an absorbing, circuit, each of said circuits including an anti-resonant reacts ance device. Signals may be formed by selectively rendering said anti-resonant devices effective or non effective as impedance elements. i I

Other'objectsof my invention, as well as details of construction, whereby myinvention may be practiced, will be apparent from the followingdescription, taken in con nection with the accompanying drawing and claims, wherein I The single figure is a diagrammatic rep: resentation ozi-circuits and apparatus .embodying myinvention, as applied to an arc: converter system i In the drawing, I have shown a iwvorlfi or radiating circuit 1 and an absorbing circuit 2, both in parallel and shunted around a source of radio-frequency currents 3. The ou c f r di -fr quen y cur nts 3.1 for. purposes ofillustration, been shown as an arc converter comprising an are 4 which maybe energized from a source of direct-current energy 5 through a pair of choke coils 6.

The absorbing circuit 2 comprises a fixed condenser 7, a tuning coil 8, an energy-absorbing element 9 and a parallel-resonant circuit 11, said last-mentioned circuit includin a variable condenser 12 and a tuning coil 14. The resistance of the coil 14 is rep ent d by a res tor 13 n Series h with. The resistance of the element 9 is such as to maintain a load upon the arc converter during the non-signaling period which issubstantially equal .to that upon the arc during the signaling period.

The. radiating circuit 1 comprises an antenna 15, a downlead 16, which connects the antenna 15 to electrode 17 of the are 4 and a g eu d condu to vl8 hich co ects the remain are e ect de 1. to aroun Ihe d wn lead T16 ,c u.de a P ral el-re onant circuit 21, comprising an inductor 14a and a resistor 13a shunted by. a condenser 12a, and a tuningcoil 22.

A switching device 23 comprises stationany contact members 24 and 25 and acoacting movable contact member or key 26. One terminal of the switch member 26 is connected to a-point 27, which is common to the radiating and absorbing circuits, while the other terminal may be actuated into engagement with the stationary contajctmembers 24 and 25. The stationary contact members 24 and 25 are connected to such points 281 and 29 in the radiating and absorbing circuits that the parallel-resonant circuits qcontained therein are selectively short circuited upon the operation of; the key26.

It will, of course, be understood that any approved tormofswitching device may be employed to effect the resultsaccomplished by the particular switching device indicated in the drawing, andthat my 'inven. tion is not to be limited thereby.

:ln-operation, the electrical time constants ,oe therpa allel resonan el -su ts ll and 2.1

are adjusted to such value that the insertion of a parallel-resonant circuit 11 or 21, in series with either the energy-radiating circuit 1 or the energyebsorbing circuit 2, causes the time constant of said energy-circuit to be greater than the time constant of the other energy-circuit which does not include a parallel-resonant circuit. It has beenfound that, when two oscillation circuits are connected in parallel across an arc oscillator, only a very small part of the oscillatingelectromotive force of the arc is effective in the circuit having'the larger time constant.

The resistances in the parallel-resonant circuits are beneficial in reducing thecirculatingcurrents produced by the small part of the are electromotive force which is effective in the energy-circuit containing a parallel-resonant circuit. I-Ience, when the key 26' is moved to short-circuit a'parallelresonant-circuit, the circulating currents in the parallel-resonant circuit are of such magnitude that they'may be short-circuited Without injury to the contact points.

lVhen the short-circuiting path is opened, the condenser 12 or the condenser 12a prevents'sparking at the contact points. How ever, if the oscillatory current builds up too quickly in the corresponding parallelresonant circuit, the oscillatory voltage across the switch may become large enough to break down the gap at the contact points after the switch becomes opened a very slight amount. The resistors 13 and 13a are, therefore, made large enough to properly damp the oscillatory currents in the parallelresonant circuits. signals are transmitted by 'moving the switch back and forth in a manner which will be obvious While I haveshown only one embodiment of my invention, it is apparent that various changes and .modifications may be made therein'without' departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed thereonas are specifically set forth in the appended claims or are imposed by the prior art.

I claim as my invention:

1. The combination with a source of oscillatory currents, of a work circuit and an absorbing circuit, both'in parallel and shunted around'said source, each o'fsaid circuits including an impedance element having a predetermined electrical time constant, and means operable to render said im edance elements effective or ineflective, sai "means including a device for selecting the element to be-efiective and the elementto be inefiective. v

v 2. The combination-with a source of oscillatory currents, of a work circuit and an absorbing circuit, both in parallel and shunted around said source, each ofsaid circuits in effective or inefiective.

3. The combination with a source of oscillation currents, of a tuned work circuit and a similarly tuned absorbing circuit, both in parallel and shunted around said source, each of said circuits including similar impedance elements having similar electrical time constants, and means operable to render said impedance elements etlective or inefiective, said means includin adevice for selecting the element to be effective and the element to be ineffective.

4. In a wireless transmission system, a source of oscillations, a radiatin circuit connected to said source, an absorbing circuit shunted around said source, each of said circuits including impedance elements having predetermined electrical time constants, and means for, at will, short-circuiting either impedance element to render the circuit containing that impedance element oscillatory and to render the remaining circuit nonoscillatory.

5. The method of signaling by means of an arc device and antenna and absorbing circuits supplied by said device which consists in alternately inserting and removing parallel-resonant reactance devices in the respective circuits.

6. The combination with a source of oscillatory currents of a tuned work circuit, a tuned absorbing circuit, and means for causing the currents from said source to flow substantially in the one or the other circuit, said means including circuit connections 'for connecting said circuits in parallel across said source, an inductive impedance device shunted by a capacitive impedance device in series relation to the circuit connections for each of said circuits, and by-pass means for varying the efl'ectiveness of said groups of parallel-connected impedance devices.

7. The combination with a source of oscillatory currents, of a tuned work circuit, a tuned absorbing circuit, and means for causing the currents from said source to flow substantially in the one or the other circuit, said means including circuit connections for connecting said circuits in parallel across said source, an inductive impedance device shunted by a capacitive impedance device in series relation to the circuit connections for each of said circuits, a by-pass path for each of said pairs of shunted impedance devices, and switching means for closing one path and. opening the other and vice versa, the relations of reactances, being such that the time constant of either circuit, with the shunted impedance devices in series, is greater than the time constant of the other circuit with the shunted impedance devices short-circuited. 7

8. The combination with a source of oscillatory currents, of a. tuned Work circuit, a similarly tuned, equivalent-energy circuit,

circuit connections for connecting said cir cuits in parallel across said source, parallelresonant, reactive-impedance means tuned to approximately the same frequency as said circuits and connected in series relation to the circuit connections for each of said cir cults, and controllable by-pass means for the respective parallel resonant means.

9. The combinatlon with a source of oscillatory currents, of a tuned work circuit,

a similarly tuned, equivalent energy circuit, clrcuit connections for connecting said c1r I cuits in parallel across said source, parallelresonant, reactive-impedance means tuned to approximately the same frequency as said circuits and connected in series relation to the circuit connections for each of saidcircults, a by-pass path for each of said parallel-resonant means, and sw1tch1ng means for closing one of said paths and opening the other and viceversa, each of said parallel-resonant means havmg a relatively small resistance and relatively large inductive and having the open-circuited by-pass path.

10. The combination with. an arc-oscillation generator, of a tuned Work circuit, a tuned absorbing circuit and means for caus ing the currents from said generator to flow substantially in the one or the other circuit, said means including circuit connections for connecting said circuits in parallel across said generator, an inductive impedance device shunted by a capacitive impedance device in series relation to the circuit connections for each of said circuits, and

by-pass means for varying the effectiveness of said groups of parallel-connected lmpedance devices.

11. The combination with an arc oscillation generator, of a tuned Work circuit, a tuned absorbing circuit and means for causing the currents from said generator to flow substantially in the one or the other circuit,

said means including circuit connections for connecting said circuits in parallel across said generator, an inductive impedance device shunted by a capacitive impedance device in series relation to the circuit connections for each of said circuits, a bypass path for each of said pairs of shunted impedance devices, and switching means for closing the one path and opening the other and vice versa, the relations of resistances and reactances being such that the time constant of either circuitwith the shunted impedance devices in series is greater than the time constant of the other circuit with the shunted impedance devices short-'circuited.

12.The combination with an arc oscillator, of a tuned work circuit, a similarly tuned equivalent-energy circuit, circuit connections for connecting said circuits in parallel across said oscillator, parallel-resonant, reactive-impedance means tuned to approximately the same frequency as said circuits and connected in series relation to the circuit connections for each of said circuits, and controllable by-pass means for the respective parallel-resonant means.

13. The combination with an arc oscillator, of a tuned work circuit, a similarly tuned equivalent-energy circuit, circuit connections for connecting said circuits in parallel across said oscillator, parallel-resonant, reactive-impedance means tuned to approximately the same frequency as said circuits and connected in series relation to the circuit connections for each of said circuits, a by-pass path for each of said parallel-resonant'means, and switching means for closing one of said paths and opening the other and vice versa, each of said parallel-resonant means having a relatively small resistance and relatively large inductive and capacitive reactances, each of said circuits likewise having, in effect, a relatively small resistance and relatively large inductive and capacitive reactances, said quantities being so chosen that there is little tendency for the oscillatory currents to flow in the circuit having the open-circuited by-pass path.

In testimony whereof, I have hereunto subscribed my name this 2nd day of August, 1921.

OMAR B. BUCHANAN. 

